Demonstration of Zr Recovery from 50 g Scale Zircaloy-4 Cladding Hulls using a Chlorination Method

Abstract

The recovery of Zr from Zircaloy-4 (Zry-4) cladding hulls using a chlorination method was demonstrated for complete conversion of Zr into ZrCl 4 . A chlorination reaction was performed by reacting Zry-4 hulls for 8 h under a 70 cc/min Cl 2 + 70 cc/min Ar flow at 380 o C. The initial weight of the reactant (51.7 g) decreased to 0.49 g after 8 h of operation, which is only 0.95wt% of the initial weight. The weight of the total reaction products was 121.7 g with a high Zr purity of 99.80wt%. Fe and Sn were identified as major (0.18wt%) and minor (0.02wt%) impurities of the reaction products, respectively. It was also shown that Zr exhibited a high recovery ratio of 96.95wt% with a relatively small experimental loss of 2.34wt%. Observation of the reaction residues revealed that the chlorination reaction was dominant along the longitudinal direction, and surface oxide layers remained as reaction residues. The high purity and recovery ratio of Zr proposed the feasibility of the chlorination technique as an effective hull waste treatment method.

Chlorination Reaction Behavior of Zircaloy-4 Hulls: A Preliminary Study on the Effect of the Oxidation Process on the Reaction Rate

“…In our previous study [13], where an extraction of Zr from oxidized Zry-4 hulls was demonstrated at a 50 g scale, the amount of reaction residue was 0.95wt%, which is identical to the case of the fresh Zry-4 of the present study. Therefore, it is not reasonable to clarify a relationship between the oxidation process and the amount of reaction residue at this stage.…”

“…Several reports were published on the treatment of cladding hull waste through the chlorination process [8][9][10][11][12][13][14][15][16].…”

“…As noted above, KAERI is working on a chlorination technique, and reported the fundamental calculation and experiment results [8][9][10][11][12][13]. The theoretical calculation results performed using the HSC chemistry code [17] revealed that the chlorination method is an efficient way to selectively recover Zr in the presence of residual SNF owing to the low sublimation temperature of ZrCl 4 and high reactivity of Zr with Cl 2 gas [9][10][11].…”

Bis(tetraphenylarsonium) hexachloridozirconate(IV) acetonitrile tetrasolvate

“…Zirconium tetrachloride is encountered in the nuclear fuel cycle for the recycling of zirconium from zirconium alloy cladding using a chloride volatility process (Bohe et al, 1996;Collins et al, 2012;Jeon et al, 2013). The ZrCl 4 produced from these alloys at temperatures above 573 K contains several impurities that are difficult to separate.…”